How would you handle this comment?

We were at my mother in laws house yesterday. We were talking about people who were having babies. I mentioned something like, "if we ever have another one..." (we have two girls now. 6 and 1.5)

And she said, "you can't even handle the two you have now! You better not have another one!"

I've been through a lot with this woman, so usually everything she says I take with a grain of salt or ignore rude comments she makes. But this kind of hurt my feelings. Maybe she didn't mean to make it sound like I couldn't handle being a mom..but she sure made me feel like a bad one.